The following
essay by Dr. Christina Leb is a summary of her recently published monograph(under the same title), which appears in Vol.
4.4, 2019, pp. 3-78, of Brill
Research Perspectives in International Water Law. Dr. Leb is a Senior Counsel at the Environment
and International Law Unit of the World Bank and a Research Fellow at the
Platform for International Water Law housed by the Faculty of Law at the University
of Geneva. She can be reached at cleb[at]worldbank.org

Cross-border data
and information exchange is one of the most challenging issues for
transboundary water management. Water data is deemed sensitive and subject to restrictions
with respect to dissemination and use in many countries. Another key challenge
is the steady decline of ground monitoring systems due to ageing equipment, and
the limited availability of resources for maintaining and modernizing these
systems according to the latest standard of technology. At the same time, data
and information availability is key to sustainable water management.

The 1997 United Nations Watercourses Convention (Art. 9) and the 2008 Draft Articles on the Law of Transboundary Aquifers (Art. 8) identify regular exchange of data and information as one of the general principles of international water law. The availability of information with respect to hydrological, meteorological, hydrogeological and ecological nature of transboundary water systems, among other, is required to implement the principle of equitable and reasonable utilization. States need to know about the natural characteristics of as well as the demands and stresses on the cross-border water system they share with their neighbours.

The main difficulty
for riparian states is to obtain all the information and data required to prepare
a detailed assessment according to the equitable and reasonable use principle.
The information needs are wide ranging and often, not all information is
available at the national level.

New opportunities for access to water related data have opened up with the
availability of technological innovations related to real-time data, space
technology, and Earth observation. These technologies have led to a drastic
increase in quality and availability of hydrological, meteorological and
geo-spatial data. In basins where seasonal flows are largely dependent on snow
pack, satellite imagery of snow cover can help identify how much and where
water is stored in the upper catchments. Information on lake and river surface
elevation can facilitate downstream flow predictions. Field-based data sources can be combined with satellite data
to further enhance forecasting and planning systems. With the help of
telemetry, data can be collected even at remote, inaccessible places and
automatically transmitted to central control points, where this data can be
converted for various applications, such as flood forecasting systems, warning
systems on toxic water pollution, and others. Hydro-meteorological models based
on real-time and historic datasets can be used to shorten lead-time and enhance
the accuracy of early warning systems.

The key legal drivers making Earth observation data more available come
from outside international water law. Space law and the framework established
by the United Nations Framework Convention on Climate Change (UNFCCC) have paved
the way for comprehensive Earth observation initiatives, and continue to
accelerate public accessibility of data and information for the benefit of all.
The outer space treaties have opened the skies to freedom of exploration and
freedom of data generation. And in line with their UNFCCC commitment to
systematic observation, states leading in space technology have made most of
their climate relevant datasets available to other nations and, to a
significant extent, the public.

Publicly available Earth observation information can be used to assess
equitable and reasonable use. These datasets reduce the amount of information
that need to be shared directly between riparian states. With the help of Earth
observation technologies, water managers can base their decision-making on
information that belongs to parts of the basin that lie outside of their own national
boundaries. The information can also be used to enhance the lead-time for
emergency notification. Additionally, the ever-increasing availability and
accessibility of data generated through Earth observation technologies may change
due diligence standards for riparian states (with respect to information gathering
and sharing) in implementing the equitable and reasonable use principle, as
well as other international water law obligations.

The monograph, published in the Brill Research Perspectives in International Water Law series, presents an exploratory assessment of the potential impacts of new data technologies on data and information exchange obligations. By highlighting the practical challenges of the use of data generated through Earth observation technologies for water management purposes, the monograph discusses how these technological innovations may, nevertheless, modify the existing contours of the rights and obligations related to data and information exchange in international water law.